U.S. Pat. No. 4,681,323 to Alaki et al. discloses a golf ball with a plurality of recessed dimples having a shape in accordance with a certain mathematical ratio on the surface thereof.
U.S. Pat. No. 4,840,381 to Ihara et al. discloses a golf ball characterized by the shape of its dimples. The dimples have a more gentle transition over their edge portion than prior art golf balls wherein dimple edges sharply intrude into the ball surface.
U.S. Pat. No. 6,331,150 to Ogg discloses a golf ball having a surface thereon with a plurality of dimples on the surface. The contour of each of the dimples is continuous from a first edge of each of the dimples to a second opposing edge of each of the dimples.
Additional background references include, for example, U.S. Pat. No. 4,813,677 to Oka et al. and U.S. Pat. No. 4,840,381 to Ihara et al.